Ring bending machines of the mentioned or of a similar type are used for annular- or ring-bending of metal pipes or solid profile rods with an adjustable bending radius in a bending plane. Such machines are common with locksmiths or plumbers (building plumbers) in order to provide bent sleepers or parts for example for railings or fences, or also bends in water pipes or heating system pipes. However, it is not possible to manufacture railing parts for spiral stairs, corresponding to a cylindrical helix (helical gradient), with such a bending machine, which provides bendings only in a single plane, i.e. the bending plane.
In order to bend pipe- or rod-shaped railing parts lying on a cylinder jacket or to bend a cylindrical coiled tubing comprising one or more turns (for example a heating or cooling coil to be housed in a cylindrical boiler or vessel), specially formed, expensive spiral bending devices are known, which, due to their high costs, can only be used cost-effectively in large firms, where an adequate work-load can be guaranteed.
It is an object of the present invention to provide an improved ring bending machine of the aforementioned type, which can easily and cost-effectively be transformed or extended into a coil or spiral bending machine, in order to be able to bend pipes or profile rods only in the ring bending plane, or with an additional helical or coil gradient extending transversely or perpendicularly to the ring bending plane.
Due to the inventive concept it is possible to convert, if the need arises, a space-saving, compact and robust ring bending machine by means of a supplementary frame having a simple and accessible structure for the manufacturing of spiral- or coil- shaped bends in a short space of time, so that the desired ring or coils bends of the metal pipes or profile rods can be provided in an exact and reproducible manner. To this effect, there are provided the two displaceable carriages for the positioning of the pressure roller, which are easily surveyable and accessible as well as exactly adjustable inside the supplementary frame mounted on the outside of the cover housing of the bending machine. The exact adjustment with respect to similar work pieces is reproduceable for repetitive bendings even if performed after intermediate bending of other pieces or after long interruption periods. The supplementary frame for performing spiral-shaped bendings can remain in its mounted state without interfering with the functioning of the machine with respect to bending operations on metal profiles solely in the ring bending plane.
In order to achieve an optimal adaptation with respect to a given space and to material feeding conditions, as well as the further transportation of bent work pieces, the ring bending machine, with or without the supplementary frame, can be operated with an arbitrary orientation, e.g. with a vertical or horizontal ring bending plane, without in any way having to accept inferior bending results. It must only be made sure that for the carrier plate, which supports the supplementary frame and all functionally important parts of the machine and to whose form the cover housing enclosing it is adjusted, there is provided, at least at its connection area adjacent to the two driven rollers, a secure connection to a robust machine or engine bed.
Typically, with ring bending machines of the aforementioned general type, a longish or elongated, slender rectifier roller is provided in the area of the runout (exit) of the profile behind the final bending roller, which has the task of holding or bending back the bent pipe profile in a homogeneous and uniform way in the ring bending plane defined by the bending rollers against its inherent stresses due to its longitudinal welding seam, which causes unwanted distortions. If this rectifier roller is transversely adjustable with respect to the ring bending plane, the annularly bent profile can be provided with a lateral bend in the sense of a helical gradient behind the final bending roller. Results of bending experiments conducted in this connection have, however, proved to be of no value, because an adjustment or displacement of the rectifier roller, which is supported at its spaced apart ends, can only be achieved in an inaccurate and cumbersome manner, and furthermore is possible only without taking into consideration the respective bending radius, and also because, due to the proximity of the rectifier roller to the exit behind the final bending roller, a danger of overstressing and non-uniform material deformations for the pre-bent pipe exists, and because, until a desired helical gradient is achieved, numerous trial runs are necessary, and even these cannot guarantee a uniform and reproduceable bending result.
According to a preferred embodiment of the ring bending machine the outline of the face sides of the cover housing, conforming to the carrier plate, corresponds to an isosceles trapezium, so that the supplementary frame can be selectively, according to the helical direction, by being mounted on one of the narrow sides of the cover housing forming the inclined (slanted) trapezium sides, fixedly aligned therewith.
Advantageously, the supplementary frame comprises two side plates stiffened with respect to one another in a spaced relation. The side plates partly cover the cover housing at its face sides and comprise connecting bores, which are aligned with respect to existing through-bores of the carrier plate and the cover housing for fixedly attaching a rectifier roller.
For calibration or retrieval of specific or known adjustment positions of the pressure roller markers displaceable with the first and/or second carriages can be provided, which cooperate with scales or dials stationarily provided on the supplementary frame or on the first carriage. In order to achieve similar results, digital counters coupled to the screw spindles of the first and second carriages with optical or acoustical indicating means can be provided alternatively or additionally.
According to a further embodiment of the ring bending machine according to the invention the second carriage can be guided in an upper member of the block-shaped first carriage protruding from the side plates of the supplementary frame, whereby the pressure roller supported on the second carriage is arranged at a substantial distance from the final bending roller forming the exit or outlet of the machine. Thus, the bending stresses induced by the pressure roller in the profile to be bent can be distributed over a larger profile length, whereby a uniform and continuous bending deformation in the sense of the helical gradient can be achieved, and nonuniform stresses, for example leading to kinks or flaws in the profile, can be avoided.